This has me stumped

65 mustang 200ci straight 6.

Has all the new tune up stuff on it
-cap and rotor
-wires and plugs
-points and condenser
-carb rebuild kit
-cleaned fuel lines and tank

it's doing some funny stuff. It'll start right up but shakes at idle. It stumbles off idle but clears up at higher rpm. I was playing with the timing, and it likes a ton of timing, it seems to clear up somewhat at 30* or so.

It's been sitting for 10+ years

So i'm guessing a couple of things, need some help on what to try first. I'm gonna try to get ahold of a compression tester tomorrow.
-Harmonic balancer spun from dry rot
-stuck lifter
-lost compression in a cylinder
-Could the points be off if the dwell is within spec?


Idk....i'm at a loss...........needs to be ready next week